N-acyl derivatives of alpha-pyridine carboxylic acid hydrazide



-tain-iiiseases of Warm-blooded animals.

United States Patent N.-A.CYL DERIVATIVES or a-PYRIDINE CARBOXYLICTAICID" "Engelbert: 'jKiihle," Leverkusien-Bayerwerk; and" Gerhard "NoiDraw'ing. Application'OctoberA, 1957 Serial 'No. 688,127-

Claims priority, application Germany November 16,1956

' 6 claims. c1. 260295) The present invention relates, in general, to thewsynthesis 'of" novel organic chemical compounds which are useful-aspharmacological agents in'the'treatment of cer- Moreparticularly,-t-he-invention contemplates the provision of novel N-acyl derivatives o'f a-pyridine 'carboxylic acid hydrazide -whichhavebeen found to be extremelyuseful as antitubercular' agents.

It has been-established, heretofore, that isonicotinic acidhydrazidccan be reacted with acylhalides or acyl anhydridesof diearbo'xylic acids to form' the isonicotinyl hydrai-i'd'e'of eyclic' dicarboxylic acids, andthattheiso- 'nicotin-yl *hydrazide of 'phthalic acid, forexampl'e,-possesses strong"tuberculostatic properties. postulated -by prior investigators that theseisonicot-inic It has also been acid derivatives represent theprobable-ultimate in such --chemotherapeutic activity, inasmuch as'the hydrazine derivatives of a-pyridine' carboxylic acid which have been 'tested heretoforearegenerally far lessactive tuberculoare highly eflicacious tuberculostatic-agents of enhanced general compatibility as compared, for example, with INH.

Thus, the principal objectiveinthe chemotherapeutic treatment of tuberculosis is the-elimination of the infecting bacteria, andidependingnponthe individual circumstances underlying the illness, .thisnecessitates prolonged treatment which may extend over many months. Accordingly, -anantitubercular agent "must not only be highly efiective against the infecting microorganism, but it must also possessparticularly goodcompatibilitywhen administered over prolonged-periods. While INH' is generally well tolerated,- it does occasionally induce undesirable side effects with some patients, particularly those which are manifested with-respect ,to,the central and peripheral nervous'system. On the other hand, it has been found that the foregoing typical-compound of the invention possesses substantiallythe samechemotherapeutic activity as INH, but is substantially more compatible than as demonstrated-by-the comparative pharmacological data presented hereinafter.

We have found that, in general, the reactions between the dicarbogiylic. -acid,anhydrides and ,q-pyridine carboxylic acid-hydrazide may be eflected at temperatures 2,996,755 Ratented ,Sept.. ,29, v.1959

within-the"range-'50 100 in organic solvents such as dioxan, ;dimethylformamide and high-boiling point hydrocarbons. The react-io nvrnay be elfected,,,also, within an aqueous phase, generally; yielding the desired end-product. The compounds of the invention are substantially all crystallineprodncts, .someoiwhich .crystallizeirom solution with one-half mole ;or one mole of water of crystalllization. V

Among the di'carboxylic acid anhydrides that'may be employed'in the process of theinvention are included, for. example, those 'ofa=phthalic .acid; .nuclearrsubstituted -phthalicacids, particularly 4-chlorophthalic acid; 1,-2- .naphthalenedicarboxylic acid; .tetrahydrophthalic acid; hexahydi'ophthaflic acid; "2;3 pyridine 'dicarboxylic acid; 3 ;6-endomethylene-A =tetrahydrophthalic acid '("3;6 '-methylene-4-cyclohexene-il,2rliearboxylic =acid), etc. In addition, -maleie anhydride and sueeinioanhydridemay also be employed as starting materials .in, the production of compounds of the; invention.

The compounds of theinventionmay.berepresented in general by the following'formulaz' t (II) whereintRi represents'ran. ethylene: or vinylene radical, or afused aromatic ringsubstituent" selected from the group consisting of benzene, qhlorohenzene,.hexahydrobenzene,

tetrahyd robenzene, naphthalene, pyridine, and '3;6- me thlylenel-eyclohexene. r It is believed that theinvention may bebest underst'ood'by reference to the following examples describing the preparation, of specific:compounds-conforming to the general formulausettforth abov e,,as,well..as;the pharma- ..colo.gical r data .ob.tained. upomtesting of Na typical, com ,pound of the invention-: 7 V v EXAMiIIE'I Preparation of the-phthalic-hydrazide of a-pyridine .fiar wfylicacid QlT U SDF (x-Pyridine-.,carbo yliczacid blfidrazide, inv amount .3 rams, was dissolved in 2100 milliliters oft-vgater-at ,-,a temperature of -7.0 "r ,Atthis temperature, ;3 7'.v grams; of -,-fihely..divided, .SOlidf phthalic anhydride ,wasadded. incremnt y-,=t the-aqueousr c ian m rt re r-Thert mrer ture rose slightly, and the desired tz pyridirte; ;z i rb onyl .qqtnpounds of the cyclic phthalie acid ;hYd 3Zide was formed; in nearly quantitative ,yield: 'I'he- -nielti ng;point for the compound. after recrystalliza tion fiom dimethylfonmamiderwater is 218 ;C.

. EXAMPLE I II Alternate synthesis for the preparationof the ph-thalic Lhydrazidev of -a-py'ridine carboxylic acid:

oc-"P'y1:idine. carboxylic t .acid'i hydrazide, in 1 amount 1 37 -gr-arns,;.was. dissolved in "200 milliliters of dimethylfbrmamide at a temperature of C. At this same temperature, a solution of 148: grams ofphthalic anhydride in 400 milliliters of dirnethylfo-rrnamide was slowly run in. The :ter'nperatureroseby a few degre w. The-reaction mixture was -stirr ed fora short ti-me,--and the desired end-product was then precipitated in the cold-by-rneans of water. The yield was- 85.5 (Melting-point 218 C) The fioregoing compound was selected for extensive pharmacological testing, andthe -data-;prese nted below =represent'the most significant-results of these tests:

Acute, toxicity-:sflgdies Groups of animals were treated with various dosage concentrations of the compound of Formula I, as administered by conventional routes, with the following results:

(A) RATS VIA ORAL SUSPENSION IN TRAGACANTH Number Number of animals Dosage level (g./kg.) of animals exhibiting Number treated toxic of deaths symptoms 5.0 3 10.0 13 0 0 1 s n 0 O (B) CATS VIA ORAL SUSPENSION IN TRAGACAN'IH (O) MICE INTRAVENOUS INJECTION 1 0.1% dissolved in a sodium hydroxide solution. 2 1.0% dissolved in a sodium hydroxide solution. 3 Spasms.

(D) RATS INTRAPERITONEAL INJECTION (E) MOUSE SUBOUTANEOUS INJECTION [Dissolved in a sodium hydroxide solution] Chronical doses (A) Cat.Tw0 test animals were given dosage concentrations of 50 mg./kg. on 12 consecutive days. Both animals survived the total dosage and a subsequent observation period of 14 days. One of the animals lost weight during the test (from 3 kg. to 2.3 kg.) while the other maintained constant weight. No symptoms were found upon routine blood testing.

(B) Rabbits.Three rabbits were repeatedly given doses of 50 mg. with an oesophageal sound. One of the animals died without symptoms after the fourth dose, and another after the ninth dose. Upon subsequent dissection no symptoms were found which could be connected with the treatment. The third animal survived a total of 12 doses and showed no toxic symptoms during a subsequent observation period of 14 days. It did not lose weight during the test, and the urine of the animal was normal throughout. The blood examination showed no symptoms.

Excretian studies The resorption of the compound from the stomach and intestinal tract, as well as its excretion through the kidney was investigated. A dog was given 0.06 g./kg. corresponding to an absolute quantity of 0.612 grams. Another dog was given 0.5 g./kg. corresponding to 13.2 grams. The compound was detected by a modification of the method of Kelly and Poet. After 1 to 2 hours blood levels could be clearly determined in this manner. The compound was partially excreted through the urine (10 to 30%).

COMPATIBILITY TESTING(INH AND THE COMPOUND OF FORMULA I).ACUTE TESTS Clzemotherapeutical testing (in vitr0).The phthalyl derivative of a-pyridine carboxylic acid hydrazide has an effectiveness against Mycobacterium tuberculosis in dilutions comparable to INH. The strains of Mycobacterium tuberculosis were inhibited on egg-media culture by dilutions of 1:50,000,000 and 1:100,000,000. The compound is a little active against INH-resistant strains as is INH itself.

Chemotherapeutic testing (in viv0).The compound was first administered to humans in the same dosage concentrations found effective for INH, i.e., 5 to 8 mg. for adults. Since the compatibility of the compound in animal tests was substantially better than that of INH, an increase of the dosage concentrations was attempted, to the extent that side efiects were not observed. Significantly, the compound was tolerated in high doses for prolonged periods. In fact, it was possible to increase the dosage concentration to double that of the general average daily doses Without undesirable side effects. The

EXAMPLE III 4-chl0r0phthalic anhydride (Melting point: 174 C.)

EXAMPLE IV H exahydrophthalic anhydride C H2 C O H o H a i. -rQ

Cfi2 \CO (Melting point=l45 C.)

EXAMPLE V 3,6-endomethylene-M-tetrahydrophthalic anhydride HO C Hate tQ Melting point=131 C.)

EXAMPLE VI Maleic anhydride HC-C 0 HCCO (Melting point=177181 C.)

The compounds of Examples III-VI were tested for in vitro activity against Mycobacterium tuberculosis (strain H37), and the following respective results were obtained:

Compound: In vitro activity Example III 1:50 mill.-1:10O mill. Example IV 1:1 million. ExampleV 1:25,0001:l00,000. Example VI 1:100,0001:l mill.

This application constitutes a continuation-in-part of our copending U.S. application Serial No. 611,363, entitled, Chemical Compounds and Process for Producing the Same, which was filed on September 21, 1956, and has since been abandoned.

Having thus described the subject matter of our invention, what it is desired to secure by Letters Patent is:

1. A chemical compound represented by the formula:

3. The chemical compound represented by the formula:

4. The chemical compound represented by the formula:

CH2 C0 5. The chemical compound represented by the formula:

6. The chemical compound represented by the formula:

No references cited. 

1. A CHEMICAL COMPOUND REPRESENTED BY THE FORMULA
 6. THE CHEMICAL COMPOUND REPRESENTED BY THE FORMULA: 